The increasing production of urban refuse is known to give rise to serious refuse disposal problems. It is now a commonly held expert opinion that one way of reducing the seriousness of the problem is to recover from the refuse those materials which can be usefully recycled, achieving the simultaneous significant advantage of reducing the quantity of refuse for disposal. It is also known that the economically most convenient moment for sorting the various types of refuse to recover material for recycling is at the formation of the refuse itself.
Refuse also occupies a volume which is normally considerable when compared with its mass. It would therefore be very convenient to be also able to reduce its volume at the act of sorting, with obvious benefits in terms of transport costs, storage, disposal or recycling.